1. Field of the Invention
The present invention relates to inspection of a defect caused by an electroluminescence element in a display apparatus having the electroluminescence element in each pixel or caused by a transistor which drives the electroluminescence element.
2. Description of the Related Art
Electroluminescence (hereinafter referred to as “EL”) display apparatuses in which an EL element which is a self-emissive element is employed as a display element in each pixel are expected as a flat display apparatus of the next generation, and are being researched and developed.
After an EL panel is created in which an EL element and a thin film transistor (hereinafter referred to as “TFT”) or the like for driving the EL element for each pixel are formed on a substrate such as glass and plastic, the EL display apparatus is subjected to several inspection and is then shipped as a product. Currently, improvement in yield is very important for the EL display apparatuses, and improved efficiency in the inspection process is desired along with improvements in the manufacturing process and materials of the EL element and the TFT.
In the inspection currently executed for an EL display apparatus, for example, faulty items such as a display defect are inspected while a raster image for each of R, G, and B or a monoscope pattern is displayed. The faulty items include, for example, display unevenness, a dark spot, a bright spot, etc.
The bright spot typically occurs due to short-circuiting of the pixel circuit or the like, and, in this case, a method is employed, for example, in which the pixel circuit is insulated through laser irradiation or the like to darken the bright spot.
On the other hand, regarding display unevenness (DIM) and dark spots, various causes are being found. For display defects which appear similar but are caused by different causes of occurrence, the cause must be identified and repairing must be applied according to the cause. However, there had not been established an efficient method of inspection according to the cause of occurrence.